Before General Albert G. Jenkins led his Confederate cavalry into Mechanicsburg on the morning of June 28, he divided his command into two wings.

General William F. Smith

Jenkins personally led two Virginia units and an artillery battery through town and out the Trindle Spring Road to Peace Church. Here, the Confederate artillery went into position and opened fire on some Union militia that they could see about a mile ahead at Oyster Point, where the Trindle Spring Road joined the Carlisle Pike.

Meanwhile, Colonel Milton J. Ferguson, leading the 16th Virginia Cavalry and 36th Virginia Cavalry Battalion, together with two cannon under the command of Captain Thomas E. Jackson, trotted out the Carlisle Pike toward Harrisburg in pursuit of a body of retreating Union militia as it withdrew down the pike. Ferguson halted his command near Orr's Bridge over Conodoguinet Creek, about a half a mile north of Peace Church and a bit farther east of Jenkins' position around the church.

The Yankee militia sparring with the Confederate horsemen was under the command of General William F. Smith, a former corps commander in the Army of the Potomac. Smith's First Division, Department of the Susquehanna, was in position to block a Confederate advance on Harrisburg. Some of his men, assisted by both white and African-American citizen volunteers, were erecting earthwork fortifications on Hummel Heights.

To protect these earthworks until they were finished and armed with cannon, Smith deployed some of his men in a line centered on Oyster Point. General Joseph F. Knipe's tired brigade, which had retreated all the way from Chambersburg, directly supported the Yankee pickets. Another of Smith's brigadiers, New York militia general Jesse C. Smith, had two regiments of his men in line as well. Captain Spencer Miller's battery of militia, just arrived from Philadelphia, provided artillery support for the nervous, untried militia recruits.

Oyster Point Tavern

After some artillery firing on the afternoon of the 28th, Jenkins pulled his men back to the Rupp House to bivouac, then moved them up to the previous day's position early on June 29. Although Captain W. H. Griffin's four cannon at Peace Church fired at the Yankees this day, Captain Jackson's two guns, positioned on the Carlisle Pike near Orr's Bridge, had a better view of the blue-coated defenders and kept up a steady, slow fire.

Suddenly, around eleven o'clock that morning, several companies of the 16th Virginia, followed by one of Jackson's cannon, came charging down the Carlisle Pike, directly at the Union militia at Oyster Point. The New Yorkers discharged a hot, though inaccurate fire that slowed down the oncoming Rebels. The charging column then ran headlong into a log and tree barricade that the militia had placed across the pike.

Their momentum slowed by the firing and the barricade, the Rebels broke and retreated, leaving their cannon near the Oyster Point Hotel. Even though the enemy had retreated, the militiamen never left their position. Later that day, they failed to dispute a second foray by Ferguson's men, who reclaimed their abandoned fieldpiece and brought it back to Orr's Bridge.

The Invasion of the North – Harrisburg, Pennsylvania.

This noisy yet brief attack, during which only two Rebels were wounded, did accomplish its goal, for it masked General Jenkins' reconnaissance to high ground south of the Union position, where three engineer officers from General Richard S. Ewell's staff examined at long range the Union defenses of Harrisburg.

Satisfied that the militia would pose no major threat, Ewell heard the report and ordered General Robert E. Rodes to move his troops forward from Carlisle and seize Harrisburg. But, on June 30, instead of heading east, Rodes marched his brigades south toward Cashtown. The Union Army of the Potomac was heading into Pennsylvania and General Robert E. Lee needed to concentrate his army.

The skirmish at Oyster's Point marked the high water mark of the Confederate advance toward Harrisburg. Only the news of the northward movement of the Union army deterred Lee from ordering the capture of Pennsylvania's capital. When Jenkins finally received word of the change of plans on June 30th, he too pulled his wing back to Carlisle and Colonel Ferguson moved his wing back to Sporting Hill before continuing west to Carlisle to join Jenkins.